Carbon nanotubes (CNTs) are promising candidates for many different applications such as sensors, supercapacitors, electrodes, drug-delivery, batteries, transparent electrodes, photovoltaic cells, digital logic (field effect transistors (FETs) and thin film transistors (TFTs)). However, one factor limiting the widespread application of CNTs is that many of these applications would require the selective deposition of a monolayer or just a few layers of CNTs from solution onto specific areas of a substrate without covering the whole substrate with a blanket film of CNTs.
Techniques have been proposed for selective deposition of CNTs onto a substrate. See, for example, Park et al., “High-density integration of carbon nanotubes via chemical self-assembly,” Nature Nanotechnology, 7, 787-791 (October 2012), the entire contents of which are incorporated by reference herein. See also, U.S. Patent Application Publication Number 2013/0082233 A1, filed by Afzali-Ardakani et al., entitled “Selective Placement of Carbon Nanotubes Via Coulombic Attraction of Oppositely Charged Carbon Nanotubes and Self-Assembled Monolayers” (hereinafter “U.S. Patent Application Publication Number 2013/0082233”) the entire contents of which are incorporated by reference herein. With these conventional processes there are, however, some notable drawbacks. For example, low densities of carbon nanotubes are observed after the deposition, the CNTs cannot be deposited over large areas, there is a lack of specificity on the interaction with the surface which leads to uncontrolled CNT deposition everywhere in the substrate, not just in the areas of interest, and there is a lack of stability of the CNT dispersion, which makes storage and use of these solutions difficult.
Therefore, improved techniques for effective, surface-selective deposition of CNTs would be desirable.